Add link to extract titles from WebM metadata.

src/General/Config.coffee

@@ -205,6 +205,10 @@ Config =
         true
         'Add sauce links to images.'
       ]
+      'WEBM Metadata': [
+        true
+        'Add link to fetch title metadata from webm videos.'
+      ]
       'Reveal Spoiler Thumbnails': [
         false
         'Replace spoiler thumbnails with the original image.'

src/General/CrossOrigin.coffee

@@ -10,8 +10,51 @@ CrossOrigin = do ->
         callbacks[id] = cb
   <% } %>
 
-  file: do ->
-    makeBlob = (urlBlob, contentType, contentDisposition, url) ->
+  binary: (url, cb, headers={}) ->
+    <% if (type === 'crx') { %>
+    if /^https:\/\//.test(url) or location.protocol is 'http:'
+      xhr = new XMLHttpRequest()
+      xhr.open 'GET', url, true
+      xhr.setRequestHeader key, value for key, value of headers
+      xhr.responseType = 'arraybuffer'
+      xhr.onload = ->
+        return cb null unless @readyState is @DONE and @status in [200, 206]
+        contentType        = @getResponseHeader 'Content-Type'
+        contentDisposition = @getResponseHeader 'Content-Disposition'
+        cb new Uint8Array(@response), contentType, contentDisposition
+      xhr.onerror = xhr.onabort = ->
+        cb null
+      xhr.send()
+    else
+      eventPageRequest url, 'arraybuffer', ({response, contentType, contentDisposition, error}) ->
+        return cb null if error
+        cb new Uint8Array(response), contentType, contentDisposition
+    <% } %>
+    <% if (type === 'userscript') { %>
+    GM_xmlhttpRequest
+      method: "GET"
+      url: url
+      headers: headers
+      overrideMimeType: "text/plain; charset=x-user-defined"
+      onload: (xhr) ->
+        r = xhr.responseText
+        data = new Uint8Array r.length
+        i = 0
+        while i < r.length
+          data[i] = r.charCodeAt i
+          i++
+        contentType        = xhr.responseHeaders.match(/Content-Type:\s*(.*)/i)?[1]
+        contentDisposition = xhr.responseHeaders.match(/Content-Disposition:\s*(.*)/i)?[1]
+        cb data, contentType, contentDisposition
+      onerror: ->
+        cb null
+      onabort: ->
+        cb null
+    <% } %>
+
+  file: (url, cb) ->
+    CrossOrigin.binary url, (data, contentType, contentDisposition) ->
+      return cb null unless data?
       name = url.match(/([^\/]+)\/*$/)?[1]
       mime = contentType?.match(/[^;]*/)[0] or 'application/octet-stream'
       match =
@@ -19,45 +62,9 @@ CrossOrigin = do ->
         contentType?.match(/\bname\s*=\s*"((\\"|[^"])+)"/i)?[1]
       if match
         name = match.replace /\\"/g, '"'
-      blob = new Blob([urlBlob], {type: mime})
+      blob = new Blob([data], {type: mime})
       blob.name = name
-      blob
-
-    (url, cb) ->
-      <% if (type === 'crx') { %>
-      if /^https:\/\//.test(url) or location.protocol is 'http:'
-        $.ajax url,
-          responseType: 'blob'
-          onload: ->
-            return cb null unless @readyState is @DONE and @status is 200
-            contentType        = @getResponseHeader 'Content-Type'
-            contentDisposition = @getResponseHeader 'Content-Disposition'
-            cb (makeBlob @response, contentType, contentDisposition, url)
-          onerror: ->
-            cb null
-      else
-        eventPageRequest url, 'arraybuffer', ({response, contentType, contentDisposition, error}) ->
-          return cb null if error
-          cb (makeBlob new Uint8Array(response), contentType, contentDisposition, url)
-      <% } %>
-      <% if (type === 'userscript') { %>
-      GM_xmlhttpRequest
-        method: "GET"
-        url: url
-        overrideMimeType: "text/plain; charset=x-user-defined"
-        onload: (xhr) ->
-          r = xhr.responseText
-          data = new Uint8Array r.length
-          i = 0
-          while i < r.length
-            data[i] = r.charCodeAt i
-            i++
-          contentType        = xhr.responseHeaders.match(/Content-Type:\s*(.*)/i)?[1]
-          contentDisposition = xhr.responseHeaders.match(/Content-Disposition:\s*(.*)/i)?[1]
-          cb (makeBlob data, contentType, contentDisposition, url)
-        onerror: ->
-          cb null
-      <% } %>
+      cb blob
 
   json: do ->
     callbacks = {}

src/General/Main.coffee

@@ -342,6 +342,7 @@ Main =
     ['Image Loading',             ImageLoader]
     ['Image Hover',               ImageHover]
     ['Volume Control',            Volume]
+    ['WEBM Metadata',             Metadata]
     ['Comment Expansion',         ExpandComment]
     ['Thread Expansion',          ExpandThread]
     ['Thread Excerpt',            ThreadExcerpt]

src/General/css/style.css

@@ -928,6 +928,9 @@ span.hide-announcement {
 .fileThumb > .warning {
   clear: both;
 }
+a.webm-title.ready {
+  text-decoration: underline;
+}
 input[name="Default Volume"] {
   width: 4em;
   height: 1ex;

src/Images/Metadata.coffee

@@ -0,0 +1,64 @@
+Metadata =
+  init: ->
+    return unless Conf['WEBM Metadata'] and g.VIEW in ['index', 'thread'] and g.BOARD.ID isnt 'f'
+
+    Post.callbacks.push
+      name: 'WEBM Metadata'
+      cb:   @node
+
+  node: ->
+    return unless @file and /webm$/i.test @file.URL
+    if @isClone
+      link = $ '.webm-title', @file.text
+    else
+      link = $.el 'a',
+        className:   'webm-title ready'
+        href:        'javascript:;'
+        textContent: 'title'
+      $.add @file.text, [$.tn('\u00A0'), link]
+    $.on link, 'click', Metadata[if link.dataset.title? then 'toggle' else 'load']
+
+  load: ->
+    $.off @, 'click', Metadata.load
+    $.rmClass @, 'ready'
+    @textContent = '...'
+    CrossOrigin.binary Get.postFromNode(@).file.URL, (data) =>
+      if data?
+        Metadata.parse.call @, data
+        $.on @, 'click', Metadata.toggle
+      else
+        @textContent = 'error'
+        $.on @, 'click', Metadata.load
+    ,
+      Range: 'bytes=0-9999'
+
+  parse: (data) ->
+    readInt = ->
+      n = data[i++]
+      len = 0
+      len++ while n < (0x80 >> len)
+      n ^= (0x80 >> len)
+      while len-- and i < data.length
+        n = (n << 8) ^ data[i++]
+      n
+
+    i = 0
+    while i < data.length
+      element = readInt()
+      size    = readInt()
+      if element is 0x3BA9 # Title
+        title = ''
+        while size-- and i < data.length
+          title += String.fromCharCode data[i++]
+        @textContent = @dataset.title = decodeURIComponent escape title # UTF-8 decoding
+        return
+      else unless element in [0x8538067, 0x549A966] # Segment, Info
+        i += size
+    @textContent = 'not found'
+
+  toggle: ->
+    @textContent = if $.hasClass @, 'ready'
+      @dataset.title or 'not found'
+    else
+      'title'
+    $.toggleClass @, 'ready'